Why calculate your 1 Repetition Maximum (1RM)?
Calculating your 1 Repetition Maximum is very important to optimize your strength training. It is even more important when starting out because we generally have no idea of the weights to use for a movement as this 1RM represents the maximum load an athlete can lift for a single repetition with correct technique.
By basing your workouts on your 1RM, you can precisely target the type of result you want to achieve, whether it’s strength, hypertrophy, or muscular endurance.
And another very important advantage for your longevity is that by knowing your 1RM, you avoid overestimating your abilities and exposing yourself to injury risks. Because the majority of injuries come from too heavy loads due to ignorance of one’s limits.
Finally, regularly tracking your 1RM is an excellent indicator of progress. We often think we are not progressing, but by regularly measuring your 1RM, you realize that year after year, if the dedication is there, your strength increases.
How to use the 1RM calculator?
To use our calculator, choose the weight unit you prefer by toggling the switch between kilograms (kg) and pounds (lbs). Then, enter the weight lifted during your last workout and adjust the slider to indicate the number of CORRECT repetitions (with perfect form) you performed on the movement. Note that the accuracy of the calculation decreases for higher repetitions.
Our calculator remains an estimate. Your true 1RM may vary slightly depending on factors such as your technique, your level of fatigue, and your condition at the time of the test.
1RM Calculator
RM Estimates
Enter your data and click Calculate
Our other calculators
If you are starting out (or if you want to be precise), other values will be important for your training. This 1RM calculator is not the only one available on our site, so we advise you to Calculate your VO2 Max if you want to be a complete athlete, but also if you want to know what muscle level you can achieve, calculate your muscle mass gain. All our calculators are also available on this page.
Interpreting your 1RM result
If you do not understand what the results correspond to, here is an example to help you. If your estimated 1RM for the bench press is 100 kg (congratulations!), the table might show:
- 95 kg (95% of 1RM) for 2 repetitions
- 90 kg (90% of 1RM) for 4 repetitions
- 85 kg (85% of 1RM) for 6 repetitions
Depending on the goal you want to achieve, here is an estimate of the number of repetitions you will need to do with the table values:
- Maximum strength: 85-100% of 1RM, 1-5 repetitions
- Hypertrophy (muscle gain): 67-85% of 1RM, 6-12 repetitions
- Muscular endurance: 50-67% of 1RM, 12-20 repetitions
IMPORTANT: Once again these values can vary according to individuals and exercises. Experience will allow you to know your body better but know that for example, exercises involving large muscle masses like the squat or deadlift can support a higher volume than isolated exercises like the bicep curl.
What is the 1RM? How is it calculated?
To calculate the 1RM, several formulas can be used. The formula we decided to use in our calculator is Brzycki’s, Why? Because it is simply one of the most accurate and commonly used:
1RM = Weight / (1.0278 - 0.0278 × Number of repetitions)This formula takes into account the weight lifted and the number of repetitions performed to provide an accurate estimate of the 1RM.
